Aiko, or Ai-chan, first appears as a transfer student from Osaka, which shows from her Osaka accent. Like a typical Osakan, Aiko is also very humorous and often cracks jokes. She's the smart aleck type of the group.

One important fact about Aiko is that she has a passion for sports, and is very athletic. She seems to fare better than her classmates and thus makes her popular in the sports department. The only sport she is weak at is swimming.

Aiko has no real love interest, but she shows affection for Leon of the FLAT4.

Aiko's birthday is November 14, her favorite color is blue, and her instrument is the harmonica. Her family consists of her divorced parents, Koji and Atsuko, and Aiko wishes one day for them to be together again.